Abstract: To reduce the adverse effects of coal gangue accumulation and save natural resources,artificial coal gangue is used as fine aggregate in concrete preparation. We conduct experimental and theoretical research on the mechanical properties of coal gangue concrete, considering the strength grades (C30, C50) and substitution rates (0%, 25%, 50%, 75%,100%) of concrete. The results indicate that coal gangue weakens the bonding performance between cement mortar and coarse aggregate transition zone; Regardless of the grade of concrete,as the substitution rate increases,the elastic modulus and axial compressive strength of coal gangue concrete decrease. When the substitution rate is 100%,the elastic modulus and axial compressive strength of C30 concrete decrease by 3. 1% and 12. 7%,respectively,while the elastic modulus and axial compressive strength of C50 concrete decrease by 6. 1% and 22. 6%,respectively. Based on the experimental results,a prediction formula for the mechanical properties of coal gangue concrete under different substitution rates was proposed.